Thallium salts in photographic color developers



Patented July 17, 1951 UNITED STATES PATENT OFFICE THALLIUM SALTS IN PHOTOGRAPHIC COLOR nEvELorERs James E. Bates, Binghamton, N, ,Y., assignor to General Aniline & Film Corporation, New York,

N. Y., a corporation of Delaware No Drawing. Application December 1, 1948, Serial No. 62,975

7 Claims. (o1. 95-583) v It has been determined that the addition of .soluble thallium salts, such as thallous and In the commercial practice of developing photographic emulsions where a large quantity of the, photographic film is to be developed, 'it is desirable that all the film be subjected to the developing solution for the same length of time. However, this is rendered difficult because if a number of. photographic films have been developed in a given solution, there is a gradual change in tone of the developed film and a loss of 'developing energy of the solution. Consequently, unless the time of development is increased it is not possible to produce a satisfactory density and contrast. Heretofore it was believed that loss in developing energy of the solution, and consequent increase in time of development was due to depletion of the developing agent and it has been proposed to maintain a relatively uniform developmenttime by replenishing the developer solution. Such replenishment has not -been satisfactory as there appears a relatively -purposes a high contrast is desirable as is the case in the development of multi-layer negative color film or multi-layer color film to be developed by the reversal process. In the development of these types of film it is highly desirable to obtain high contrast While at the same time maintainthallicnitrate, thallous and thallic sulfate, thallous hydroxide, thallous chloride, thallous bromide and thallous iodide to the color developer for color development of multi-layer photographic color emulsions of the negative and reversal type. materially improves the developing characteris tics and prolongs the life of the developer.

The actionof the thallium compounds on the color developer is such that it will effect the revivification of exhausted developer solutions. In applying the invention to the revivifying of such developer solutions, a soluble thallium salt is intermittently added in small increments during the development process. The required amount of the soluble thallium salt may be introduced intermittently after a predetermined quantity of hausted. If desired, the developer and other in:

ing the time of development as small as possible.

In the color development of color film of the negative or reversal type containing color formers in a plurality of layers the shortened development time considerably reduces color fog or stain. It is, therefore, an object of this invention to so improve the color developing solution employed in the color development of photographic negative and reversible type color emulsions as to eifect a shortened development time for the same gredients of the developing solution may also be replenished by addition of suitable quantities of developer, preservative and alkali, along with suitable quantities of the soluble thallium salt to maintain the desired properties. In this method of replenishing developer solutions, a relatively small quantity of the soluble thallium salt is used, preferred amounts being about 0.001 to 0.005 gr. per square foot of emulsion developed, depending upon'the degree of exhaustion of the developer.

' In order to obtain the maximum elfect on contrast; rate of development and emulsion speed, the soluble thallium salt is added to the fresh developer solution before commencing to develop color negative or color reversal emulsions therein. It has been determined that quantities of thallium salts as small as 0.005 gr. per liter of the color developer solution produced noticeable effects on these color emulsions. Concentrations ashigh as 0.5 gr. per liter have also beenfound useful, but the acceleration effect reaches an optimum at from .05 to 0.2 gr. soluble thallium salt perliter of the color developer solution.. .As compared with my companion application 783,-

v 224, filed October 30, 1947, wherein soluble thaldegree of development and consequent reduction lium salts are employed in the black and white *duced by use of the solublethallium salts in the color developer for color negative and color reversible film emulsions and in the case of color negative film emulsions the thallium salts in the color developer also produce steeper gradation than can be obtained'by-any modifications of the development time.

The color developers with which the soluble thallium salts are used may include the usual color developers employed for development of color negative films and for color development of reversible color films of the multi-layer type containing color formers in a plurality of layers. These color developers contain suitable aromatic primary amino developing agents which are characterized by the presence of a free or primary amino group which enables the oxidationproduct v of the developer to couple with the colorformers' in the film emulsion to form a dye image in the emulsion layer adjacent to the individual particles of the silver image which has been formed by exposure. The primary amino developing agents ordinarily employed are p-phenylene diamines, particularly those having one of the amino groups alkyl substituted. Examples of such ,developing'agents include p-phenylene diamine, monoethyl-p-phenylene diamine, ortho aminodiethyl aniline, 4,4 diamino diphenylamine, p-amine dialkyl anilines, p-amino-diethyl-aniline and p-amino-dimethylaniline. These developing agents are'preferably used in the form of their'salts'such as the hydrochloride since the salts are more "soluble and stable than'the free base. the developer has pro'duced'adye image, the silver image may be removed bybleaching in the'usual well known manner to'leave the color-image in the film emulsion.

A suitable developing solution for color development may be prepared as follows:

P-amino diethyl-aniline .HCl gr 2.0 Sodium carbonate .(anhydrous)n gr 350.0 Sodium bisulfite ...gr

Potassium bromide gr 0.2

are added to :suflicient water to make one liter. Hydroxylamine hydrochloride may be added in amounts of approximately 1 .gr. to such a .developing solution for the .color development .of color negative emulsions. The ingredients of this typical developersolution may be varied and amounts of the .soluble thallium salts, such as thallous nitrate, may be added within the range of from .005 to 0.5gr. per liter toproduce the desirable effects of this invention.

The following examples will-serve'tofurther illustrate this invention and the best manner .of

carrying it out, it being understood that the vmaterials and preparationstherein recited are given by way of illustration and not intendedaslimitations. Unless otherwisespecified, .thepartsare by weight.

Example '1 P-amino diethyl-aniline HCl 'gr 3.0 Sodium-bisulfite 'gr. :120 Sodium carbonate, monohydrated.. ;gr 60.0 Hydroxylamine HClT gr 1:0 Eotassium bromide -gr ,.1;

Water to make 1.0 1.

such as After the action 'of 4 2. Short stopped 1' in the following solution:

Sodium acetate gr 20.0

Acetic acid e .sl cc 10.0 Water to .make 1.0.1. I I

h 3. Hardened 5 in the following solution:

Potassium chromealum, 30.0 gr. I Water to make 110 l. -.4. Washed 5' inrunning water.

' 5. Bleached 10 in the following solution:

=6. Washed "5 in running water.

7. Fixed 5' in the following :solution:

Sodium thiosulfate, 200.0 ,gr. Water to make 1.0.1.

8. Washed 10 in running water and dried.

An identically exposed piece of negative "color film having the same characteristics as the film treated in'the example was given the same-processing as above with the exception that'0.05' gr. per liter of thallous nitrate were addedtoth color negative developer. The same l2'develqping time was employed. When-the two resultant colornegatives' were compared photographically', the negative processed with 'the'thallous nitrate displayed 3/ stop more .emulsion speed and WQ'S considerably steeper in-gradation, particularlyin the cyan layer, than the. normallyprocessed'strip. [A thirdpiece-of :the .colornegativefilm identically exposed-:and processed :throu h :rthe original .set of solutions, except that .;the dBVfil-s opment time was increasedfrom'al2 to 18'. man attempt to achievethe accelerated developing effects 'obtainedas above'by addition of-the thal lous nitrate. Thisincrease -of development-time effected an increaseinthe emulsion spee'd of I stop,but gave considerably increased .fog to the developingcolors aniifididnotproduce any steep ening of the gradationcomparable .to that,pr.o-v duced by .the thallium vcontaining developer in the .12 development.

Example 2 A -multi layer color film of the reversal ztype containing dye coupling substance in a "plurality of the individual "layers was-given a nor-' mal camera-exposure "and'processed by "the following procedure: I

1. First developed12 at 68 in the following solution: i

Metol gr- 3E0 sodiumi'sulfite gr 5.0. 0 Hydroquinone gr 6 50 Sodium carbonate ;gr 40.0 Sodium thiocyanate gr 210 Potassiunrbromide. l gr,, .21) Water. to makelufl l. g I

"'2. LRinsed -l in'runnin-g water. j

' 3. Hardened. '5 in -a;'3'% solution "of "potassium chrome alum. f I

5.'Color developed 16' in the following solu tion: g j

P-amino diethyl-aniline HCl 'r 4.0' Sodium bisulfite gr 1.0 Sodium carbonate gr 67.5

Potassium bromide gr 2.5

Water to make 1.0 l.

6. Short stopped 2' in the following solution: Acetic acid cc 10.0 Sodium acetate gr 20.0 Water to make 1.0 l:

7. Hardened in a 3% potassium chrome alum solution.

11. Fixed 5 in 20% hypo solution. 12. Washed and dried.

A similarly exposed piece of color film of the reversal type having the same characteristics as the film treated in this example was processed according to the same procedure, with the exception that 0.5 gr. perliter of thallous nitrate were added to the color developer solution and the color developing time was reduced from 16' to 9. Substantially the same degree of development was obtained by this shorter development time in the solution containing the thallous nitrate and in addition the highlight stains were reduced perceptibly. No increase in contrast resulted in this instance, but that could not be normally expected with reversal film processing since the final contrast is substantially determined by first development and in this case the accelerator was added to the color developer.

Example 3 Additional pieces of reversal type color film having the same characteristics as that used in Example 2 were processed according to the procedure outlined in Example 2, with the exception that the following color developing solution was used:

P-amino dihydroxy-ethylaniline sulfate gr. 6.0 Sodium bisulfite gr. 1.0 Sodium carbonate gr. 100.0 Potassium bromide gr. .0

Water to make 1.01.

This color developing agent was found to be much less energetic in its developing energy than the p-aminodiethyl-aniline I-ICl used in Example 2. Even with a formula of increased strength, as given above, a developing time of 30' was necessary to secure the desired density and color balance. However, upon adding 0.1 gr. per liter of thallous nitrate to this color developer and reducing the color developing time to the same color density and gradation was obtained as in 30 time with the developer containing no thallous nitrate. Also the film developed 15' in the developer containing the thallous nitrate was considerably less stained than the film processed in the normal manner.

Example 4 A multi-layer negative color film containing dye couplers in a plurality of the individual layrs was given normal-camera exposure and then processed by the followingprocedure:

1. Developed ,12' at 68 F.- with the following" color negative developer:

P-amino 'diethyl-aniline HCl gr. -3.0 Sodium bisulfite gr. 1.0 Sodium carbonate, monohydrated gr. 60.0 HydroxylamineHCl gr. 1.0 Potassium bromide.,, gr. 1.0:

Water to make 1.0 1.

' 2; Short stopped 1 in the following solutionf Potassium bromide gr 15.0 Disodium phosphate gr 13 .0 Sodium bisulfate ..gr 6.0

Water to make 1.0 l.

6. Washed 5, in runningwater. 7. Fixed 5' in the followings'olution:

Sodium thiosulfate, 200.0 gr. Water to make 1.0 l.

8. Washed 10' in running water and dried.

An identically exposed piece of negative color film having the same characteristics as the film treated in the example was given the same processing as above with the exception that 0.100 gr. per liter of thallous iodide were added to the color negative developer. The same 12' developing time was employed. When the two resultant color negatives were compared photographically, the negative processed with the thallous iodide displayed /2 stop more emulsion speed and was considerably steeper in gradation, particularly .in the cyan layer, than the normally processed strip.

A third piece of the color negative film was identically exposed and processed through the original set of solutions, except that the development time was increased from 12 to 18' in an attempt to achieve the accelerated developing effects obtained as above by addition of the thallous iodide. This increase of development time effected an increase in the emulsion speed of A; stop, but gave considerably increased fog to the developing colors and did not produce any steepening of the gradation comparable to that produced by the thallium containing developer in the 12 development.

I claim:

1. The method of developing an exposed hotographic element having at least one silver halide emulsion layer containing color formers which will couple with the oxidation product of a phenylene diamine developing agent which comprises subjecting such an exposed photographic element to a color developer solution comprising a phenylene diamine developing agent having at least one primary amino group and a soluble thallium salt, the latter being in the concentration of 0.005 to 0.5 gram per liter of solution.

2. The method of claim 1 in which the soluble thallium salt is thallium nitrate.

. 3;. A photographic. developersolution'foreolon development: of a photographic element having; v

atv least one silver halide emulsion layer containprimary amino group and a soluble;thalliumisaltr the latter being in the concentration. of 0.065;- 0.5- gram per liter of solution. I

4. The photographic developer solutionLzof claim. 3.wher.ein the soluble thallium saltis thallium nitrate. 5. A photographic developer'solution for" color development of a photographic element having at least one silver halide emulsion-layer containing color formers which will couple withthe oxidation product of a phenylene diamine developing agent which comprisesa p-amino di ethyl aniline salt and a soluble 'thalliumsalt the latter being in the. proportion :of- 0.005 to. 0.5. gram per liter of solution. ,1v 6. A photographic developer solution for color developmentof a photographic element having at least one silver 'halide'emulsion layer. containing color formers which will couple with the oxidation product of a phenyleneldiarnine developing agent which comprises aj p-amino' diethyl aniline salt and a soluble thallium salt,

the latter being in -the'proportion of10.05.gram 9.

per liter ofsolution. a

.5.: Band '13, 1937, pp. 129434.

.. oxidation-product of a phenylene diaminedeveloping agent-which comprises p-amino di-' ethyl 'ani'l-ineHCl salt and thallous nitrate, the; latter being in the proportion of 0.05 gram per liter ofsolution.

JAMES E. BATES.

REFERENCES CITED 'ljhe following. references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,105,214 Steigman Jan. 1.1.,v 1938s FOREIGN PATENTS j -Number- Country Date- 477,628 Great Britain Jan. 4, 193-1- OTHER REFERENCES Haidrich, Photographische Korrespondenz,

(Copy in Scientific Library.)

} Haidrich, Photographische Korresponde'nn. Band '74, 1938, pp. 8-13. (Copy in Scientific; Library.) A 

3. A PHOTOGRAPHIC DEVELOPER SOLUTION FOR COLOR DEVELOPMENT OF A PHOTOGRAPHIC ELEMENT HAVING AT LEAST ONE SILVER HALIDE EMULSION LAYER CONTAINING COLOR FORMERS WHICH WILL COUPLE WITH THE OXIDATION PRODUCT OF A PHENYLENE DIAMINE DEVELOPING AGENT WHICH COMPRISES A PHENYLENE DIAMINE DEVELOPING AGENT HAVING AT LEAST ONE PRIMARY AMINO GROUP AND A SOLUBLE THALLIUM SALT, THE LATTER BEING IN THE CONCENTRATION OF 0.005 TO 0.5 GRAM PER LITER OF SOLUTION. 